


Unmistaken Identity

by DirtyKnots



Series: Kinktober 2017 [16]
Category: Teen Wolf (TV)
Genre: Alternate Universe - High School, Alternate Universe - Human, Anal Fingering, Anal Sex, Angst, Blowjobs, Derek and Stiles are brothers, Falling In Love, First Time, Frottage, Incest, M/M, Mildly Dubious Consent, Rimming, Sibling Incest, Underage Drinking, Underage Sex, Unsafe Sex, mistaken identity (but not really)
Language: English
Status: Completed
Published: 2018-03-07
Updated: 2018-03-07
Packaged: 2019-03-28 04:37:46
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 7,289
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13896423
Author URL: https://archiveofourown.org/users/DirtyKnots/pseuds/DirtyKnots
Summary: Kinktober2017 - Day 16Waxplay||Pegging||MasksSometimes you can't help who you love, even if it is your brother. Just ask Cersei Lannister.





	Unmistaken Identity

**Author's Note:**

> Read the tags. In this 'verse, Stiles and Derek are full blood relatives (siblings). Stiles is 14, Derek is 18. If you have a problem with either of these things, don't read the fic.

Stiles isn't sure what’s happened over the last few years. He and his brother had always been close as kids, but the second that Derek entered high school, it all seemed to change. He missed it, missed days filled up with video games or baseball in the park. Derek had been his best friend, not just his brother. And sure, he has Scott now, but it isn't the same. Now he's finally back in the same school as Derek, but that only seems to make it worse, make the gap more obvious. Like, he understands that it isn't common for an 18-year-old senior to hang out with his 14-year-old kid brother who's only a freshman. He gets it. But it sucks, and it hurts, to watch Derek's eyes skate over him in the hallways like he’s invisible.

***

Stiles stops bothering to try and ask Derek for a ride after the first week. Half the time he's long gone before Scott and Stiles even make it out of the school anyhow. The Stilinski house is always quiet when he gets home too, empty. Stiles has no idea where Derek goes off to, but he hasn't spent an afternoon with his brother since Derek's freshman year. It's been a long three years of loneliness. It's not as bad when Scott comes over, but between his mom's work schedule and the new girl who he's started fixating on, it doesn't happen all that often. Stiles resigns himself to hours of homework and solo gaming before he starts on dinner, knowing he's probably the only one who will eat when it's hot. Their dad's been picking up longer hours at the station ever since their mom skipped out a couple years back. It's hard to keep up with the cost of two teenagers. Stiles feels bad and wishes he could do more to help, but at least he cooks so their dad doesn't have to worry about that too.

Stiles is used to being ignored, to coming home to an empty house, to seeing Derek at dinner only (if even then). It sucks, but it's been normal for so long now. It's the end of October when things change. Their dad has to go out of town, some training convention for a week. Derek is a legal adult, so John feels confident leaving Stiles with him.

“No parties, no drinking. I'll be home next Monday morning, there's money in an envelope on the fridge for groceries and pizza.” John ruffles their hair on his way out the door, Stiles and Derek side by side waving him off. As soon as the cruiser is out of sight, Derek grabs the keys to the Camaro, left behind by their mom when she split, and takes off. No backward glance, no goodbye. Something deep inside of Stiles aches as he locks the door behind his brother before climbing the stairs and giving in to the increasing urge to lay down. 

Stiles sends a text to Derek when he gets up, asking if he'll be home for dinner so that he knows how much food to make, but it had goes unanswered. He makes plenty anyways, because even if Derek is acting like an asshole, Stiles doesn’t need to be one. He's just finished wrapping up Derek's to put away when he hears the front door open. He moves from the kitchen to the hall, mouth open to call out, plate still in his hands when he sees what's going on. Derek's back is to him, body pressing someone against their front door, hips grinding. And the sounds. Stiles’ heart does a stutter stop before racing away as watches a long nailed hand grip at his brother's ass, and the next thing he knows the plate he's been holding is crashing against the floor, food spilling, porcelain shattering all over the wood. Derek spins toward the noise, pulling his body away from the girl. Stiles’ skin feels hot, his hands shaking slightly, a weird tightness in his throat that he doesn't understand. 

“Stiles?” Derek's face is scrunched a bit in confusion, whether it's because of the dropped plate or whatever expression is written on Stiles’. Stiles swallows hard, fighting the growing lump in his throat and the prickling in his eyes (and seriously, what the fuck is up with this, he doesn't understand why he's suddenly this upset). He fish-mouths for a few seconds, unable to make words happen before he turns on his heel and books it back down the hall and up the stairs. He doesn't stop running until his door slams behind him and he collapses backwards against it, sliding to the floor. 

“What the fuck is wrong with me?” The words are a whisper, his breath hitching as he feels the first few tears slip free. He buries his head in his hands, knees drawn up to his chest, as he cries. He can hear raised voices from downstairs, they go on for a few minutes before the front door slams. It's quiet for a little while, long enough that he manages to cry himself out. He's curled on his side on the floor when he hears Derek coming up the stairs. There's a knock, but he just curls up tighter, doesn't say anything. He hears the sigh before Derek speaks.

“Stiles...are you okay?” It's soft, hesitant.

“What do you care?”

“I care.”

“Could've fooled me,” Stiles mumbles as he scrubs at his face, the words muffled through his sleeves.

“Stiles…”

“Just leave me alone, you're good at that.” He thinks he hears the catch of Derek's breath, but Stiles ignores it, just reaches up and turns the lock before crawling to his bed, kicking off his shoes, sliding under the covers, and burying his head beneath the pillow. He's nearly out when he hears Derek finally give up and move away, thinks maybe he hears the front door open and close but he's too close to sleep to be sure, and doesn't care enough to fight the fog that's dragging him under.

***

Stiles wakes with a stuffed nose, his eyes feeling tender and raw from the crying the night before. He makes quick work of stripping down to his boxers, tossing the dirty laundry in a corner to be dealt with later, feeling a little stupid for how he reacted, thinks maybe he owes Derek an apology - it's not like he'd said anything untrue, but he also kinda acted like a brat for no reason. He grabs his towel and moves to the hall, heading towards the bathroom. He can see Derek's bed where the door is cracked, looking empty and unslept in. He gets the weird pained feeling again before he rolls his eyes and shuffles along to the bathroom. His towel goes on the rack and he bends to peel off his boxers when he's startled by a choking sound from behind him. He jumps and spins, hands holding his crumpled underwear in front of his junk to find Derek in the doorway. Derek's eyes are shut tight, tips of his ears red. Stiles’ gaze catches on the way Derek is gripping the towel around his own waist, slung low and exposing the cut of his hips. He flushes when he realizes what an eyeful Derek must have gotten with the way he been bent over. Feels an odd stirring in the pit of his belly, blood following the blush further south. And oh, oh shit. No. 

“Jesus Derek, knock maybe?” He's trying to hide the growing feelings with mock irritation, tries to snarl out the words. It drags an equally bitchy reply.

“Try shutting the door next time then.” Derek snaps as he reaches into the bathroom to grab the knob and yank it closed before stomping off down the hall. Stiles assumes he's going to their dad's room to use his shower. 

“Dick!” He can't really let Derek get the last word, and he locks the bathroom door as he yells, just in case. He doesn't get a response, doesn't really expect one. The boxers get tossed in the corner and he turns on the water to heat while he brushes his teeth. He's still running the last few minutes over in his head when he steps into the shower and groans at the sudden warmth. His mind keeps replaying the seconds immediately after he'd heard Derek behind him. The flush of embarrassment, the rush of...something when he'd seen the way the towel hung on Derek's frame. It's...wrong. He knows it. They're brothers. And yet.

Stiles doesn't even realize he's started stroking himself, hands soap-slick on his cock. He yanks them back, thumping his head against the wall and trying to think of something else, anything else, to get himself under control. He's softening, almost able to get back to washing up before he has to catch the bus to school when he hears a moan echoing through the wall. He'd nearly forgotten the bathrooms shared a wall, and he almost thinks he imagined it until it comes again. He finds himself dipping past the spray, cheek pressing to the cold tile just under the shower head. There's no mistaking it when it comes again, Derek's voice, moaning, muffled words he can't really make out. Jesus. He's jacking off in the other shower, just a wall between them. Stiles has a minute to wonder who his brother's thinking about, a moment for his brain to supply that maybe it's him - he did give Derek a little show earlier after all.

Stiles tries to put the brakes on his train of thought, but his mind races ahead without him. He's scooting back into the spray, squirting more shower gel into his palms before bring them around, one stroking his cock, the other trailing across his belly, around his sides, over his ass-cheeks. His mind paints a picture, re-creating and changing the scene from earlier. Derek stepping up behind him as he's bent over undressing. His palms cupping Stiles’ cheeks, pulling them apart, holding him open while he looks his fill. Stiles can feel his hole twitching, slips a soapy hand between the cleft, only jolts a little as the pad of his finger rubs across his pucker. He settles quickly, imagines it's Derek touching him. He strips his cock faster as he circles his hole with two fingers now, inching closer, adding pressure. The tip of one finger slips in just as he comes, body tensing and bowing around it, hand stilling on his cock. He thinks he may have shouted when he came, isn't sure. There are spots in his vision. He's careful when he drags the tip of his finger back out, feels the way the tight ring of muscle tugs, shudders a bit. He's still coming down when he hears the front door slam, followed quickly by a screech of tires as Derek peels away. Just as quickly as the high from coming appeared, it flashes away, replaced by a consuming wave of guilt. He'd just gotten off to thoughts of his own brother.

“Seriously, what the fuck is wrong with me?” The patter of water on the porcelain tub is the only answer he gets.

***

The guilt is eating him alive by the time Stiles gets to school, and he's grateful for the first time all year that this is the one place he knows for sure Derek will avoid him. Except suddenly that's not the case. Stiles has spent most of the last few days not seeing Derek around school at all and now his brother seems to be everywhere. Coming down the hall at the same time, heading into the bathroom Stiles was walking towards, just behind him in the cafeteria line. It's too much, between the night before and the incident this morning (and okay sure, Derek doesn't know that Stiles jerked off to the thought of him, but the fear that he'll see it written all over Stiles’ face is enough)...Stiles can't take it. He drops the half-full lunch tray onto the counter before he even makes it to the register to pay and just books it out of the cafeteria. He thinks he hears someone calling after him but he doesn't stop, not even at his locker to grab the rest of his things. The doors aren't usually guarded so he has no trouble leaving the school, taking the back way home just in case any of his nosy neighbors are out. His dad may be out of town but they all have his number, and Stiles doesn't have a good explanation to give if his dad calls to see why he's home in the middle of the day. He'll worry about the truancy call he’s sure to get later. He's barely set foot inside the back door when he hears a familiar engine roar into the driveway, door slamming as soon as the car cuts off. 

“Fuck my life.” Stiles debates turning right back around but knows he'd have to come home eventually. At least now Derek can yell or whatever he plans to do and then Stiles and his shame can go hide back in his room. It's not like Derek can make him go back to school or anything. Well, not unless he carries him back, and Stiles is pretty sure his brother won't stoop to that (but oh god how hot it is just thinking about Derek lifting him up, hands on his a- nope, not going there). Stiles glares at his crotch, willing his semi to go away, disappointed in his cock for not listening to the shame and guilt and staying soft. It refuses to listen so he gives up and slumps into one of the kitchen chairs, hoping the table and his baggy jeans hide it well enough. Derek rounds the corner a second later, eyes wide, eyes darting over Stiles, expression vacillating between worried and pissed.

“What the hell Stiles? You can't just take off because dad's gone!”

“That's not-”

“You're lucky he added me to your guardian paperwork with the school. I had to make up a lie about how you were throwing up to sign us both out so they didn't call dad. I mean, seriously, what the fuck? First you flip out last night, now this.”

“I...Der-” Stiles can feel his heart pounding, feel his stomach churn at the disappointment and anger he can see in Derek's face. His chest is getting tight and he can feel the tell-tale prick of tears, again, and he just can't. “Fuck this.” It's barely a whisper as he pushes back from the table and rushes past Derek, taking the stairs two at time and flinging himself onto his bed, curling into a ball as he starts to cry. He's only there a minute before his bed dips and there's a warm palm spread across his back rubbing soothing circles.

“Stiles, talk to me. What's going on with you lately? You're not yourself. I know I haven't been around as much-”

“At all.”

“What?”

“At all, Derek. You haven't been around at all.” Stiles rolls over, sad to lose his brother's hand on him, but needing to face him for this. It's been building up for so long. He runs his sleeve across his face, wiping away the remnants of tears and snot. He can't do anything about the state of his face, sure that it's red and puffy from crying about all this again. “We used to be close. You used to be around and we'd hang out and then you went to high school and it's like you forgot about me. And now that I'm there too I thought it would go back to how it was but it's like I don't even exist.” He's hyperventilating a bit by the time he finishes, and Derek rests a palm on his chest, dragging one of Stiles’ to his own, reminds him to breathe. He's not having a panic attack - though he used to get them after their mom left - but his chest is almost as tight as when he has one. Derek starts talking, keeping up the gentle pressure to the rhythm of his own breaths.

“Stiles - I didn't...things are different. We're older and it's not going to be the same, you're not-” Derek's not even looking at him and Stiles can't take it, yanks his hand back while shoving Derek's off of him.

“You used to care. You say it's different but it's not. I still love you, don't you love me too?” There's a whine in his voice and he thinks that's more honest than he ever meant to be. Because he did change, he knows...the way he felt last night and this morning. It is different. Derek's looking at him with wide eyes and it's too much, he turns his face away.

“Stiles, I do love you. You're my brother, I'm always gonna love you.”

“That's not-” It may be true, but it isn't what Stiles means anymore, and even as Derek reaches out to drag him into a hug, Stiles is twisting away, but Derek doesn't give up, just wraps his arms around Stiles even as he starts to cry again, because this is maybe worse than how he felt when he thought Derek hated him. It's not enough. Not what he really wants, and he knows how wrong it is, how it won't ever be what he needs. He cries until his body gives up and he drifts into blackness, Derek's arms still around him, his voice whispering nonsense into Stiles’ ear.

***

Stiles wakes to his hips rocking backward, a warm weight settled half over him that he's grinding against. There's a hardness pressing against his ass to match the one he's sporting. His mind’s a little fuzzy, but it feels good so he doesn't think to hard about it, just rocks his hips faster. He's getting close, thinks whoever is behind him might be too, if the growing wet spot he can feel seeping through his jeans is any indication. He's so close, almost there, can feel his balls drawing up tight when the body behind him lets out a startled yelp and is suddenly flung away. Stiles wakes all the way then, sitting up abruptly, hands dropping to cover his crotch, doing his best not to squeeze and stroke it through his pants. He's afraid to look but can't stop himself, sees Derek sprawled on the ground, the front of his khakis showing a growing wet circle. Stiles can see the utter look of shock on Derek's face as he stares at his own crotch, expression giving off the vague impression that he thinks his body has somehow betrayed him. It's a feeling Stiles understands. 

“Derek I-”

“I have to go.” Stiles can't even finish apologizing before Derek is up and gone, the door to his room shutting loudly behind him, not quite slammed.

“Fuck.” Eventually, when there's still still radio silence from Derek's room, Stiles gives in and grabs clean clothes before hauling himself to the shower. He has half a mind to jerk off but stops when he remembers Derek's face, feeling ill. There's no way Derek doesn't know now why Stiles has been so all over the place. He was grinding into him like he was hoping Derek's cock would somehow jump through two layers of pants and end up inside his ass. He can only guess at how disgusted with him Derek must be right now. 

Derek's gone by the time he gets out of the shower, and he doesn't bother answering Stiles’ texts the rest of the night. Stiles feeds himself leftovers and goes to bed later than usual since their dad is gone and tomorrow is a Saturday. Derek still isn't home. 

He's still gone when Stiles gets up in the morning, or gone again. It hurts, but he knows it's his own fault. He resolves to find a way to apologize, to promise he'll stay away, that even though they're brothers, he'll leave Derek alone from now on. He's just sitting down to brainstorm when there's a knock at the door, and when Stiles opens it, Scott's on the other side.

“Heeeey Scotty, you look….why are you dressed like Batman?” 

“Dude, it's Halloween. Why aren't you dressed up?” Stiles had totally forgotten. He remembers now how they'd argued back at the start of the month about why Stiles, who loves Batman, was stuck as Robin. Scott had won the argument solely because the last costume remaining was his size, and sadly way too big on Stiles. 

“Right. Listen man, I'm not really in the mood to go trick-or-treating. We're kinda too old for that now anyhow.” His voice trails off, right hand reaching up to scratch at the back of his neck. Scott's face scrunches up and he pushes past Stiles and into the house as he starts talking.

“I know man, we're not doing that. I heard about a party at that old abandoned house out in the preserve, it's gonna be crazy. Like, half the school is going. Get dressed, if we head out now we can catch the last bus to the edge of the preserve, then it's not too far in.

“Scott -”

“Stiles, dude, come on. Lydia will be there!” And there's no way to explain to Scott why he couldn't care less about the girl he once thought he'd marry, so after a bit more pestering he gives in. Maybe he'll get lucky, find someone not related to him to hook up with and fix whatever made him fall for his own brother. He shakes it off as much as he can and goes to change. The outfit is...it doesn't leave a lot to the imagination. He never should have agreed to it, it's old-school Robin, tights and all. On a whim he slips into Derek's room, rifles around in his nightstand drawer until he finds a small, half-empty bottle of lube which he shoves into his boot (it's not like he has pockets). He heads to the bathroom to spray his hair before strapping on the mask and giving himself one more look over to make sure it's all as in place as it can be. He's surprised by his reflection, with the black hairspray, the mask, and most of his skin hidden by the costume he's pretty unrecognizable. The spandex clings to his body in a way that he thought would be embarrassing but actually looks pretty good - he'd never really noticed how much more defined his muscles had become from playing lacrosse. Or, well not playing, but practicing at least. The costume makes him look good, not built by any stretch, but definitely toned. Maybe his chance of finding someone to hook up with isn't as slim as he thought it was.

***

By the time they make it to the party, it's fully dark out and Stiles regrets ever being Scott's friend. He'd sworn up and down that he knew a shortcut through the woods to the old house, which is why they'd been walking for over an hour and Stiles was pretty sure he'd give up and die right where he was if they couldn't finally hear the thumping bass of music and loud whine from the generators someone had brought. Stiles almost does collapse on what used to be the lawn when they break out of the treeline. The only thing that stops him is his desire to not make an ass of himself and give away who he is. He doesn't look like himself so he's decided he's not going to be himself tonight. 

The front yard is crowded, kids spilling off the rickety porch and all over the clearing. He doesn't spot anyone he can recognize on sight and is more than happy to follow Scott (and the line of drunken revelers) inside the house and towards the kitchen, where all the booze is currently hiding. He found the stash of red cups and let someone pump beer into it. He downs the first cup and gets a second before wandering back out towards the living room, the music so loud he can't even think. The few lights scattered around give just enough illumination that he can see a writhing mass of people on the makeshift dance floor, grinding on one another, sweat and glitter glistening in the laser lights someone set up. Stiles finishes the second cup, limbs feeling a little looser, and glances around to realize he lost Scott already. He'd be more sad about it if his hips weren't already rolling with the beat, feet carrying him into the crush of bodies. 

Stiles ends up in the middle of the crowd somehow, arms in the air, body gyrating to the music. It isn't long before there's a warm weight plastered to his back, fingertips pressed into his hip bones, moist heat against the side of his neck where the other person has pressed their mouth. In the flashes of light he can see large hands, dark hair dusting the knuckles. The mouth on his skin has stubble attached to it, rough in contrast to a weird smoothness that surrounds it. He reaches a hand up, sliding along where the guy's face should be, feeling some sort of material instead - latex maybe. Stiles’ fingers run down the side, coming into contact with a jacket collar, the neck of the mask slipping down beneath it. He gives up and hooks his hand around the back of the guy's head, applying a little pressure, encouraging him to keep playing his lips and tongue across the exposed bits of Stiles’ neck. His ass pushes back more insistently, grinding against the growing hardness. He has a brief flashback to the evening before, to the way he'd been practically dry-humping his brother, but he pushes the thoughts away, pulls himself back into the moment.

The underlying beat of the music is slow and sinuous, it's easy to lose himself in it, letting his body undulate in time with it, feeling the rhythm of the guy behind him match it. The guy alternating nibbles, kisses, and wet suction against Stiles’ throat, no doubt leaving a ring of marks behind, his hands sliding across the spandex encasing Stiles’ body, over his hips and thighs, up his chest, skating low across his belly, wrist dragging just above where Stiles’ cock is hardening. It's going to be an obvious and maybe vaguely embarrassing situation soon, if anyone pays attention, the costume really doesn't leave room for it not to be. He's debating whether to turn around or pull away entirely, get some distance, when the guy behind him finally gets tired of skipping around what he really wanted. One of his hands slips down and cups Stiles’ cock, fingertips dancing over the head, thumb stroking over the shaft, pairs it with a particularly hard suck over one of the tendons in Stiles’ neck, causing them both to moan. Stiles’ free hand moves between them, groping for the guy's cock as well. He's barely got a hand over the bulge before the guy is moving out from behind him, has a second to maybe worry but his hand is being enveloped and he's being tugged away from the crowd and up the sketchy looking stairs.

Stiles can finally get a good look, the guy is in sinfully tight jeans, his hardness glaringly easy to spot. His shirt seems molded to his body, muscles rippling and bunching with each step. He does have a leather jacket on, despite the heat inside the house from the crowd, and topping it all is a latex wolverine mask, yellow nearly glowing in the dimness. His eyes are hard to make out past the shadows the mask is casting on them. His mouth though...there's a large cutout for it, pink lips glistening with what's probably his own saliva (Stiles can feel a coolness where his neck is still went from the guy's mouth after all) and surrounded by dark stubble. Stiles’ own lips tingle when he thinks about that stubble running across them. The first few rooms they pass are occupied by people in various states of undress and Stiles is about to suggest they just stop where they are, but the last room is surprisingly still empty. There's an old mattress in the corner and that's all Stiles has time to see before the guy is dropping his hand and spinning him around, pushing him up against the door he'd shut behind them.

Stiles’ imagination doesn't hold a candle to how good the guy's lips actually feel when they press against his. The kiss is like liquid fire, all heat and tongues. He can barely breathe for it, his mouth being devoured, the guy's tongue fucking into it. Stiles’ hands wander, drifting over the guy's back and ass, dragging him closer, grinding into him. He doesn't know how long it goes on, is dizzy from so little air and the rush of blood south, but too soon it feels like, the guy is pulling away, flinging his jacket off towards the bed and dropping to his knees, mouth latching onto Stiles’ bulge and sucking him through the stretchy fabric. His own knees try to buckle, but then there are strong hands on his hips, holding him up, pinning him against the wall. He can feel the way he's jerking in the grip, trying to thrust further into the warm wet of the guy's mouth.

“Fuck me,” it's barely more than a whisper but it's the first time either of them have spoken since this all started. The guy freezes below him, and Stiles worries that maybe this dude knows who he is now - his voice is recognizable to most of his classmates - and is going to lose interest. He starts to straighten up, getting ready to leave the room, but the guy's mouth is still over his clothed dick, and as he shifts, trying to pull back, the suction returns, the hands holding him briefly tighten before slipping around to caress his ass, sweeping over and between his cheeks. At the first hint of pressure against his hole, Stiles bucks forward, his own hands dropping to the guy's shoulders (and fuck him the muscles there). The sucking begins to die off, turns more into his cock being nuzzled at before the guy stands, hooking his arms under Stiles’ thighs as he rises, lifting him and tossing him onto the mattress.

“Fuck yes,” it's definitely louder than his last exclamation, and the guy lets out a dark chuckle, dropping down by Stiles’ feet. He unlaces Stiles’ boots with care, smirking when he drags them off and the lube falls out. Stiles flushed but the guy merely retrieves it and drops it next to Stiles’ hip. He drags the spandex pants down, smiling when Stiles’ cock pops free, giving it a quick stroke before he leans back and undoes his own jeans, freeing his cock as well. Stiles watches, gaze hungry, as the guy kicks off his boots and shimmies the rest of the way out of his pants, stripping his shirt over his head before dropping back down and motioning at Stiles’. He hurries to comply, almost losing his mask before the guy rights it. When he's as bare as the guy (the masks are apparently staying on and Stiles wants to be bothered because this is his first time, but also it's kind of unbelievably hot), they come back together, the guy's weight heavy over Stiles’ body, and oh fuck, that is another cock touching his cock and he bucks up into the sensation, swallowing the startled laughter of the guy on top of him in another bruising kiss. 

They make out fervently for awhile, hips grinding into one another, sweat pooling between them, and then the guy is slithering down Stiles’ body, hooking Stiles’ knees over his shoulders, and Stiles thinks for a second the guy is going to continue what he started earlier. There's a quick flash of a tongue running down his cock, but it doesn't stop at the base, laving over his balls before traveling lower. He can feel warm pants of air on his hole, cheeks held open by large palms, and he can feel himself twitching - in anticipation or nervousness, he's not really sure. He doesn't get long to worry before the guy's mouth is sealing over him, tongue alternating between running flat and wide over him and flicking at his hole. He can feel himself giving in and relaxing as the guy practically makes out with his rim, forcing himself to stop fighting against it because maybe it's a little weird (he's been sweating in spandex for hours now and also, nobody has ever really been that close to his ass before), but it's also good. It's warm and wet and it's sending sparks of pleasure through his body. His back arches off the mattress when the guy spears his tongue and fucks it right inside of Stiles. He's pretty sure he yells too, but it's not like anyone could hear it. It seems to drive the guy into a frenzy and he keeps it up, alternating with sucks at Stiles’ rim, yanking at his hips to pull him harder against his mouth. Stiles can feel his cock leaking like a faucet, precum running down his belly, thinks he's gonna cum from this alone. He's nearly there, balls starting to tighten, when the guy backs off.

Stiles is pretty sure he lets out a whine, gets another chuckle in reply, but the guy doesn't start back up, instead grabbing the lube and slicking his fingers. Stiles watches him roll it around before he drags his hand down to Stiles’ ass, starts gently circling his rim. Stiles is pretty relaxed from having his ass eaten, barely twitches when the first finger is buried inside him. It's quickly followed by another, and the gentle pressure of being stretched is familiar - he's done this to himself after all. He makes an impatient noise, asks for another and is rewarded with the third and a quick jab at his prostate. The stretch is more noticeable this time, but it doesn't burn, just feels good, and soon enough Stiles is moving his body to meet each thrust. 

“I'm good, fuck me, please.” The fingers inside him still, and Stiles tries to grind himself down to keep up the friction, but they're carefully slipped free. The guy drizzles more of the lube onto his own cock, hissing at the cool sensation, and urges Stiles over and onto his knees, helping draw his hips up to the right angle. The guy rubs his cockhead over Stiles’ hole a few times, holding Stiles still when Stiles tries to thrust back onto him when it catches on his rim. He seems satisfied after a minute, thumbs digging into Stiles’ ass cheeks as he holds him open. He pushes forward slowly, the tip of his cock spreading Stiles’ hole as it breaches him. Stiles can't stop the moan he lets out, or the clench of his rim around the intrusion. The pace stays slow and careful until the entire cockhead pops inside,and then he stops. Stiles thinks he's being given time to adjust, but when it's clear he has and the guy still isn't moving, he throws a puzzled look over his shoulder. The guy is smirking, hands still holding Stiles’ cheeks apart, but no longer putting any pressure to hold him still,and he realizes what the guy is waiting for. He drops his forehead to his arms, feels his cock twitch beneath him, and then starts his own slow push backwards, spearing himself on the guy's cock. He's panting by the time his ass meets the guy's hips, can feel the gentle sway of the guy's nuts bouncing against his own. 

This time he does need a minute to adjust, because damn if this guy isn't thick, and far longer than Stiles’ fingers. It feels good, it's just a lot, and he says as much. He takes a few deep breaths, lets his body relax into feeling so full, and then starts shallowly fucking himself on the cock inside him. His arms and thighs are burning after only a few minutes, but the guy seems to understand, hitches Stiles’ hips a little higher, presses down on his shoulders until Stiles’ head is resting on the mattress, then tightens the grip on his hips and starts to drive into him. It feels amazing, his body writhing and tensing as the guy fucks into him with abandon, cock glancing off his prostate every few thrusts. Eventually the guy drops down, weight enveloping Stiles, bracing himself on one arm and grinding his hips in hard rolls, with the occasional thrust, his other hand reaching around and stroking Stiles’ neglected and leaking cock. 

“Fuck baby, feel so good, taking my cock so well. God, I love you. Wanted this for so long, but I didn't think- fuck.” The guy's hips start to stutter, and it's that more than anything that catches Stiles’ attention, makes him focus on the voice in his ear, because he fucking knows that voice. Except it can't be. It couldn't possibly be…

“God, you have no idea. Seeing you all the time. And that day. Your fucking hole. I wanted to eat you up, fucking wreck you.” Jesus, it is, and Stiles is pretty sure he's not even aware of what he's saying or else he'd stop. “Can't even be around you, can barely hide it. It's so wrong but I don't care, fuck. I need you. Fuck. Fuck fuck fuck, Stiles.” It's a drawn out moan, the guy's hips hitching, and Stiles can feel his balls drawing up tight as he shifts enough to move his own hand down, wrapping it around the one stroking his cock, wedging their fingers together as they bring him off.

“Fuck, Derek, yes.” He knows what he's doing as he starts to cum, ripples his ass around his brother's cock where it's buried inside him, feels Derek shove deep one last time before his body goes rigid as he pumps his load inside of Stiles. He half collapses onto him, and Stiles has enough presence of mind to shift their hands away from his now spent cock. And to twine their fingers together more tightly. It was a good plan because as soon as Derek's brain kicks back on, he's trying to pull away - probably to run like he had the night before.

“Nope, nuh-uh. You're staying here until we talk.” Stiles keeps his grip tight as he rolls over, shoving his mask up and off while he's at it. Derek's own face is turned away, body half-curled into itself and he flinches back when Stiles grips the bottom of his mask and starts to tug it off. Stiles doesn't relent and eventually Derek reaches up with his free hand to help. His hair is plastered to his head with sweat once he's finally free of it, and Stiles has to resist the urge to ruffle it up. “Derek, hey, look at me, talk to me.” He punctuates it with a squeeze to the hand he's still holding, and it takes a second before Derek's head turns, eyes lifting to meet Stiles’. The naked fear there makes something in Stiles' clench, but he doesn't say anything, waits for Derek.

“I'm sorry. I shouldn't have-” And that's not right, not at all what he wants to hear, so Stiles cuts him off before he can get going. Just flings himself into Derek's lap and presses a gentle kiss to his mouth to shut him up.

“Please don't be sorry about this. I'm not.” Derek’s head drops forward, forehead resting against Stiles’, free arm coming up to encircle him. He doesn’t seem ready to talk, but at least he’s not trying to run. “I came here tonight hoping to find someone to take my mind off of you. I didn’t think this would ever happen, that you’d want me back, that you’d be okay with it. I thought, after last night, that you wouldn’t want anything to do with me again. That I’d ruined everything, even just a chance to get back what we had before.” He takes a breath, tries to think of how to continue, but Derek speaks before he has a chance.

“I didn’t know it was you, at first, tonight. I thought maybe it was someone who had a similar build, I didn’t - I should’ve, the moles I mean, I know what yours look like, all of them, exactly where they are. I’ve been staring at them my whole life, so I should’ve known. I don’t know, maybe part of me did. But when we got up here and you spoke, I knew and I didn’t stop. I thought I should, but I couldn’t. The way you felt in my mouth, under my hands - I’ve been dreaming of this for so long. I thought maybe I could have it, have you, just this once, and nobody had to know. What would it hurt? You’d have a first time with someone who loved you, who’d make it good. You didn’t have to know it was me. Last night, when we woke up, I thought you’d been doing it in your sleep - that you forgot I was there, thought I was someone else...but you didn’t, did you? And then tonight - I didn’t know I was talking, but then you said my name, and I thought I’d fucked up, was gonna lose you forever. But it was worth it anyhow, just to have you at least once. To show you how much I love you.”

“How long?”

“What?” Derek looks startled, eyes finally lifting to catch on Stiles’.

“How long have you been in love with me?” There’s a flush creeping up Derek’s neck and he’s trying to turn his face away again, but Stiles releases his hand, brings both palms up to cup his face, and whispers it, lips nearly touching Derek’s. “How long?”

“Years.” The longing in his voice is unmistakable and Stiles presses forward the rest of the way, lips parting, tongue flicking out to taste Derek’s mouth. They kiss for a few moments, his skin heating up again, the fire that never really went out reigniting in his belly.

“You have me now. I’m all yours.”

“Stiles, we can’t. It’s wrong - we’re brothers. It’s illegal.”  
“I don’t care. No, listen,” Derek was trying to draw away again, but Stiles just wraps his legs around his brother’s waist, holds his face more firmly. “Derek, I don’t care, we’ll figure it out. We’ll find a way to make it work. Please, I love you. I want you. I need you. Don’t leave me.” He can hear the desperation in his own voice, doesn’t care, and sighs in relief when Derek’s mouth crashes back into his, his brother’s arms tightening around him, pressing them together as closely as he can. When they break for air, there’s a bit of shine to Derek’s eyes.

“Okay, Stiles, okay. We’ll figure it out. I love you too. I won’t leave you, not ever.” Derek follows it up by rolling them over, Stiles beneath him again on the mattress, his weight a comfort over Stiles’ body. It’s so easy to fall together again, now that they know. It will be harder tomorrow, and the day after, but they have all the time in the world, Stiles thinks. They’ll figure out how to stay together.

**Author's Note:**

> Come find me on [DreamWidth](https://dirtyknots.dreamwidth.org/), all of my additional contact information can be found there or on my [Profile Page](https://archiveofourown.org/users/DirtyKnots/profile) here (including where you can leave me prompts of your own)!


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